Darien Houser was convicted of the 2004 killing of a Philadelphia warrant officer attempting to serve a warrant on Houser for failing to appear at his rape trial.
John Koehler Jr. is on death row for persuading a teenager to kill Koehler's girlfriend and her 9-year-old son in Bradford County in 1995.
Willie Clayton was found guilty in 1986 of killing two Philadelphia men during separate robberies, two months apart.
Pennsylvania has executed only three people - all of whom chose to end their appeals - since the U.S. Supreme Court restored the death penalty in 1976. The last was in 1999.
